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Rewrite the physreg part of findLastUseBefore().

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To find the last use of a register unit, start from the bottom and scan
upwards until a user is found.

<rdar://problem/13353090>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176706 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen
2013-03-08 18:08:57 +00:00
parent e77b6ceb02
commit 778ef97c76
2 changed files with 76 additions and 24 deletions
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lib/CodeGen/LiveIntervalAnalysis.cpp
+36 -24
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@@ -972,9 +972,9 @@ private:
// Return the last use of reg between NewIdx and OldIdx.
SlotIndex findLastUseBefore(unsigned Reg) {
SlotIndex LastUse = NewIdx;
if (TargetRegisterInfo::isVirtualRegister(Reg)) {
SlotIndex LastUse = NewIdx;
for (MachineRegisterInfo::use_nodbg_iterator
UI = MRI.use_nodbg_begin(Reg),
UE = MRI.use_nodbg_end();
@@ -984,30 +984,42 @@ private:
if (InstSlot > LastUse && InstSlot < OldIdx)
LastUse = InstSlot;
}
} else {
MachineInstr* MI = LIS.getSlotIndexes()->getInstructionFromIndex(NewIdx);
MachineBasicBlock::iterator MII(MI);
++MII;
MachineBasicBlock* MBB = MI->getParent();
for (; MII != MBB->end(); ++MII){
if (MII->isDebugValue())
continue;
if (LIS.getInstructionIndex(MII) < OldIdx)
break;
for (MachineInstr::mop_iterator MOI = MII->operands_begin(),
MOE = MII->operands_end();
MOI != MOE; ++MOI) {
const MachineOperand& mop = *MOI;
if (!mop.isReg() || mop.getReg() == 0 ||
TargetRegisterInfo::isVirtualRegister(mop.getReg()))
continue;
if (TRI.hasRegUnit(mop.getReg(), Reg))
LastUse = LIS.getInstructionIndex(MII);
}
}
return LastUse;
}
return LastUse;
// This is a regunit interval, so scanning the use list could be very
// expensive. Scan upwards from OldIdx instead.
assert(NewIdx < OldIdx && "Expected upwards move");
SlotIndexes *Indexes = LIS.getSlotIndexes();
MachineBasicBlock *MBB = Indexes->getMBBFromIndex(NewIdx);
// OldIdx may not correspond to an instruction any longer, so set MII to
// point to the next instruction after OldIdx, or MBB->end().
MachineBasicBlock::iterator MII = MBB->end();
if (MachineInstr *MI = Indexes->getInstructionFromIndex(
Indexes->getNextNonNullIndex(OldIdx)))
if (MI->getParent() == MBB)
MII = MI;
MachineBasicBlock::iterator Begin = MBB->begin();
while (MII != Begin) {
if ((--MII)->isDebugValue())
continue;
SlotIndex Idx = Indexes->getInstructionIndex(MII);
// Stop searching when NewIdx is reached.
if (!SlotIndex::isEarlierInstr(NewIdx, Idx))
return NewIdx;
// Check if MII uses Reg.
for (MIBundleOperands MO(MII); MO.isValid(); ++MO)
if (MO->isReg() &&
TargetRegisterInfo::isPhysicalRegister(MO->getReg()) &&
TRI.hasRegUnit(MO->getReg(), Reg))
return Idx;
}
// Didn't reach NewIdx. It must be the first instruction in the block.
return NewIdx;
}
};